Because the Uda V5 driver operates at kernel level (Ring 0), a maliciously modified version can completely own your system. Never download the driver from generic "driver update" websites.
If you get an error like Permission denied: '/dev/ttyS0', your user does not have dialout permissions.
Fix: Uda V5 Driver
sudo usermod -a -G dialout $USER
# Log out and log back in for changes to take effect
Cause: Windows Update has reinstalled default security policies. Solution: Permanently enable test mode: Because the Uda V5 driver operates at kernel
bcdedit /set testsigning on
Restart. A watermark will appear, but the Uda V5 driver will load. Restart